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Pika

A pika, blending in with its surroundings, carries greenery to its haystack. Yellowstone provides classic talus habitat for pikas.

NPS/Janine Waller

The pika (Ochotona princeps) is considered an indicator species for detecting ecological effects of climate change. While abundant in the Greater Yellowstone Ecosystem, pika numbers are declining in some areas of lower elevations in response to increased warming, which reduces their suitable habitat. While the recent US Fish and Wildlife Service review of the pika found no current need to list the species as threatened or endangered, pikas will likely disappear from some lower elevation or warmer sites.

Pika track

Number in Yellowstone

Abundant.

Where to See

Mammoth and Tower areas, most often.

Identification and Behavior

7–8.4 in. long, 5.3–6.2 ounces (about the size of a guinea pig).

Active year-round; agilely darts around on rocks; travels through tunnels under snow.

Breed in spring; two litters per year.

Often heard but not seen; makes a distinct shrill whistle call or a short “mew.”

Grey to brown with round ears, no tail. Blends in with rocks.

Scent marks by frequently rubbing cheeks on rocks.

In late summer it gathers mouthfuls of vegetation to build “haystacks” for winter food; defends haystacks vigorously.

Haystacks often built in same place year after year; have been known to become three feet in diameter.

Like rabbits and hares, pika eat their own feces, which allows additional digestion of food.

Habitat

Found on talus slopes and rock falls at nearly all elevations in the park.

Management Concern

Pikas are vulnerable to loss of habitat related to climate change.

Behavior

Pikas are territorial. They inhabit rocky alpine and sub-alpine zones feeding on the vegetation that fringes their preferred talus slopes. Because pikas do not hibernate, this relative of the rabbit must gather enough plant materials during the short growing season to survive the winter. Piles of drying vegetation, called haystacks, and a distinctive high-pitched call are the most recognizable indicators of active pika habitat. Prolific breeders, pikas usually have two litters of young each summer. The mortality rate is high for the youngsters and the first litter has a greater rate of survival. These small mammals are sensitive to temperatures above 77.9°F (25.5°C); therefore, they are most active during cooler parts of the day.

Research

The National Park Service stewards pika populations in more than a dozen parks and seeks to understand the vulnerability of pikas and other mountain species to climate change. Pikas in Peril, funded in 2010, was a collaborative research program directed by scientists from the National Park Service, Oregon State University, University of Idaho, and University of Colorado-Boulder.